US4902308A
Expired / Lapsed
US
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Composite membrane
Assignee: W.L. Gore and Associates Inc
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Filing: 1988-06-15
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Granted: 1990-02-20
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Expires: 2008-06-15
Abstract
Abstract A porous composite membrane is provided comprising a film of porous, expanded polytetrafluoroethylene whose surfaces, both exterior and within its pores, are coated with a metal salt of a perfluoro-cation exchange polymer. Also provided is the method of avoiding false-positive detection of the presence of organic nerve gas agents by a sensor adapted to detect such presence by employing in the sensor a porous composite membrane comprising a film of porous, expanded polytetrafluoroethylene whose surfaces, both exterior and within its pores, are coated with a metal salt of a perfluoro-cation exchange polymer, the composite acting as a scavenger of unwanted gas components which cause the false-positive signals.
Inventors
- 👤 Robert S. Mallouk
- 👤 Phillip A. Branca
Bibliographic Details
Application Number
—
Jurisdiction
US
Data Source
google_patents
Last Synchronized
2026-10-30 18:30
CPC Classifications
B; B01; B01D; B01D67/00; B01D67/0081; B01D67/0088; B01D71/00; B01D71/06; B01D71/30; B01D71/32; B01D71/36; C; C08; C08J; C08J5/00; C08J5/20; C08J5/22; C08J5/2206; C08J5/2275; C08J5/2281; G; G01; G01N; G01N27/00; G01N27/26; G01N27/28; G01N27/40; C08J2327/00; C08J2327/02; C08J2327/12; C08J2327/18
Claims Analysis
Total Claims: 14
Claim 1
Independent Claim
30 words
A porous composite membrane comprising a film of porous, expanded polytetrafluoroethylene whose surfaces, both exterior and within its pores, are coated with a reactive metal salt of perfluoro-cation exchange polymer.
Claim 2
Dependent Claim
30 words
A porous composite membrane comprising a film of porous, expanded polytetrafluoroethylene whose surfaces, both exterior and within its pores, are coated with a reactive metal salt of perfluoro-cation exchange polymer.
Claim 3
Dependent Claim
15 words
The composite membrane of claim 1 wherein said perfluoro-cation exchange polymer is perfluorosulfonic acid polymer.
Claim 4
Dependent Claim
15 words
The composite membrane of claim 1 wherein said perfluoro-cation exchange polymer is perfluorocarboxylic acid polymer.
Claim 5
Dependent Claim
25 words
The composite membrane of claim 1 wherein saidmetal salt is a salt of a metal from Group I B of the periodic table of elements.
Claim 6
Dependent Claim
14 words
The composite membrane of claim 1 wherein said metal salt is a silver salt.
Claim 7
Dependent Claim
17 words
The composite membrane of claim 1 wherein said metal salt is a salt of a polyvalent metal.
Claim 8
Dependent Claim
18 words
The composite membrane of claim 1 wherein said perfluoro-cation exchange polymer has an equivalent weight less than 1000.
Claim 9
Dependent Claim
63 words
The composite membrane of claim 1 wherein said film of porous, expanded polytetrafluoroethylene has a thickness between about 1 mil and about 6 mils, a methanol bubble point as measured by ASTM F316-80 between about 7 and about 26 psi, air flow as measured by Gurley densometer according to ASTM D726-58 between about 3.5 seconds and about 50 seconds and porosity exceeding 60%.
Claim 10
Dependent Claim
24 words
The composite membrane of claim 1 wherein the weight fraction of perfluoro-cation exchange polymer exceeds 0.08, based upon the total weight of the composite.
Claim 11
Dependent Claim
41 words
The composite of claim 1 wherein the air flow of the composite as measured by Gurley densometer according to ASTM D726-58 is greater than 10 seconds and the thickness of the composite is between about 1 mil and about 5 mils.
Claim 12
Dependent Claim
47 words
The composite of claim 10 wherein the air flow is between 12 seconds and 22 seconds, the thickness of said composite membrane is between 1.7 mils and 3 mils and the weight fraction of perfluoro-cation exchange polymer exceeds 0.12, based upon the total weight of the composite.
Claim 13
Independent Claim
72 words
The method of avoiding false-positive detection of the presence of organic nerve gas agents by a sensor adapted to detect said presence by employing in said sensor a porous composite membrane comprising a film of porous, expanded polytetrafluoroethylene whose surfaces, both exterior and within its pores, are coated with a metal salt of a perfluoro-cation exchange polymer, said composite acting as a scavenger of unwanted gas components which cause said false-positive signals.
Claim 14
Independent Claim
72 words
The method of avoiding false-positive detection of the presence of organic nerve gas agents by a sensor adapted to detect said presence by employing in said sensor a porous composite membrane comprising a film of porous, expanded polytetrafluoroethylene whose surfaces, both exterior and within its pores, are coated with a metal salt of a perfluoro-cation exchange polymer, said composite acting as a scavenger of unwanted gas components which cause said false-positive signals.
References Cited (Backward Citations)
USPTO Annuity & Maintenance Windows
| Annuity Stage | Window Opens | Payment Deadline | Surcharge Period Until | Estimated Fee | Status |
|---|---|---|---|---|---|
| 3.5 Years (Year 4) | 1993-02-19 | 1993-08-21 | 1994-02-20 | $2000.00 | Window Closed / Lapsed |
| 7.5 Years (Year 8) | 1997-02-19 | 1997-08-21 | 1998-02-20 | $3760.00 | Window Closed / Lapsed |
| 11.5 Years (Year 12) | 2001-02-19 | 2001-08-21 | 2002-02-20 | $7700.00 | Window Closed / Lapsed |